1. Field of the Invention
The present invention relates to a novel antimicrobial agent for infectious diseases caused by Gram-negative as well as Gram-positive bacteria and to a process for the production of the same. More particularly, the invention pertains to a cephalosporin of the formula (I): ##STR4## wherein A, R, M and X are as described hereinafter and pharmaceutically acceptable salts thereof and to process for the preparation thereof.
2. Description of the Prior Art
It is known that cephalosporin series compounds such as Cephalothin and Cefazolin are very effective and are widely used as chemotherapeutic agents for infectious diseases caused by Gram-positive or Gram-negative bacteria.
However, these cephalosporin series compounds have no effect on infectious diseases caused by Pseudomonas aeruginosa which have been increasingly spreading in recent years, and are often very difficult to cure. Cephalosporin series compounds which are effective against Pseudomonas aeruginosa are not yet commercially available.